Mulit-purpose contact lens care compositions

ABSTRACT

Multi-purpose solutions for contact lens care provide substantial lens wearer/user comfort and/or acceptability. Such solutions include an aqueous liquid medium; an antimicrobial component, preferably a biguanide polymer present in an amount of less than about 5 ppm; a surfactant component, preferably a poly(oxyethylene)-poly(oxypropylene) block copolymer surfactant, in an effective amount; a phosphate buffer component in an effective amount; a viscosity inducing component, preferably selected from cellulosic derivatives, in an effective amount; and a tonicity component in an effective amount. Such solutions have substantial performance, comfort and-acceptability benefits, which, ultimately, lead to ocular health advantages and avoidance of problems caused by contact lens wear.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to compositions for treating, forexample, disinfecting, cleaning, soaking, conditioning and wettingcontact lenses. More particularly, the invention relates tomulti-purpose solutions useful in treating contact lenses, for example,for disinfecting contact lenses, for removing deposit material fromcontact lenses, for soaking, conditioning and/or wetting contact lensesand the like, which provide substantial comfort and acceptabilitybenefits to the users of such solutions.

[0002] Contact lenses need to be periodically treated, for example,disinfected, cleaned, soaked and the like, on a regular basis because ofthe tendency for a variety of ocular and environmental contaminants,microbes and other materials to accumulate on the lenses and/or the needto provide the lenses in suitable condition for safe and comfortablewear. User compliance, that is users treating contact lenses on aregular and consistent basis, is important in order to promote ocularhealth and to avoid problems associated with contact lens wear. Usercompliance is enhanced when the treatment solution employed provideshigh degrees of lens wearer/user comfort and acceptability. Therefore,it would be advantageous to provide compositions for treating contactlenses which provide such comfort and/or are accepted by contact lenswearers/users of such compositions.

[0003] Fu U.S. Pat. No. 4,323,467 discloses an aqueous compositioncombining a poly(oxyethylene)-poly(oxypropylene) substitutedethylenediamine surfactant, a germicidal agent, a viscosity builder, atonicity agent, a sequestering agent and water for treating rigidcontact lenses. This patent discloses a germicide, such as thimerosaland/or benzalkonium chloride, in a concentration of 0.0005%-0.05%. TheFu patent does not disclose the use of any specific buffer. Although thecompositions of the Fu patent have multiple utilities, there is apotential for eye discomfort and/or irritation, for example, because ofthe relatively high concentrations of germicide and the apparent lack ofpH control.

[0004] British Patent 1,432,345 discloses a contact lens disinfectingcomposition including an ophthalmically acceptable biguanide in a totalamount of from 0.0005% to 0.05% by weight. This British patent disclosesthat the solution preferably has a pH of from 5 to 8 and employs aphosphate buffer. The patent also discloses employing additionalbactericides, thickening agents and non-ionic surfactants, as well asdisodium EDTA in concentrations of at least 0.1%. Although thesecompositions are effective as contact lens disinfectants, they do pose arisk of eye discomfort and/or irritation, for example, because of therelatively high concentrations of biguanide and EDTA employed.

[0005] Ogunbiyi et al U.S. Pat. No. 4,758,595 discloses an aqueoussolution of a biguanide in an amount of 0.000001 to 0.0003% weightpercent in combination with a borate buffer system, EDTA, and one ormore surfactants. This U.S. patent additionally states that conventionalbuffers, other than the borate buffer, can be used but only inconjunction with increased amounts of biguanide. Thus, the generalconclusion of this U.S. Patent is that if reduced amounts of biguanideare to be used, a borate buffer is essential. Although such compositionsare useful, the potential for ocular discomfort and irritation in arelatively large percentage of the total population still exists, forexample, because of the requirement that a borate buffer be employed.

[0006] There continues to be a need to provide new contact lenstreatment systems, for example, multi-purpose solutions, that effect thedesired treatment or treatments of the lens and, at the same time,provide substantial, preferably enhanced, lens wearer/user comfort andacceptability.

SUMMARY OF THE INVENTION

[0007] New compositions for treating contact lenses have beendiscovered. The present compositions, that is multi-purpose aqueoussolutions, include antimicrobial components, preferably reducedconcentrations of antimicrobial components, in combination withphosphate buffers and viscosity inducing components to provide thedesired antimicrobial activity and performance effectiveness and,importantly, substantial, preferably enhanced, lens wearer/user comfortand acceptability benefits. These compositions are surprising andunexpected in view of the above-noted prior art which employs relativelylarge concentrations of antimicrobial components and/or bufferingsystems other than phosphate buffering systems and/or does not employviscosity inducing components. In addition, the inclusion of one or moreother components in the present compositions is effective in providingadditional beneficial properties to the compositions, and preferablyprovide further lens wearer/user comfort and acceptability benefits. Thepresent compositions have a multitude of applications, for example, asdisinfecting, cleaning, soaking, wetting and conditioning compositions,for contact lens care, while providing substantial lens wearer/usercomfort and acceptability. The present compositions preferably increaseuser compliance, that is promote regular and consistent contact lenscare, and, ultimately, lead to or facilitate better ocular health.

[0008] In one embodiment of the present invention, multi-purposesolutions for contact lens care are provided. Such solutions comprise anaqueous liquid medium; an antimicrobial component in an amount effectiveto disinfect a contact lens contacted with the solution; a surfactant inan amount effective in cleaning a contact lens contacted with thesolution; a phosphate buffer component in an amount effective inmaintaining the pH of the solution within a physiologically acceptablerange; a viscosity inducing component present in an effective amount;and a tonicity component in an amount effective in providing the desiredtonicity to the solution.

[0009] The antimicrobial component may be any suitable, preferablyophthalmically acceptable, material effective to disinfect a contactlens contacted with the present solutions. Preferably, the antimicrobialcomponent is selected from biguanides, biguanides polymers, saltsthereof and mixtures thereof, and is present in an amount in the rangeof about 0.1 ppm to about 3 ppm or less than 5 ppm (w/v). The preferredrelatively reduced concentration of the antimicrobial component has beenfound to be very effective, in the present compositions, in disinfectingcontact lenses contacted with the compositions, while at the same timepromoting lens wearer/user comfort and acceptability.

[0010] Any suitable, preferably ophthalmically acceptable, surfactantcomponent which is effective in cleaning contact lenses may be employed.The surfactant component preferably is non-ionic and, more preferably,is selected from poly(oxyethylene)-poly(oxypropylene) block copolymersand mixtures thereof.

[0011] Any suitable, preferably ophthalmically acceptable, viscosityinducing or thickening agent may be included in the presentcompositions. The viscosity inducing component preferably is selectedfrom cellulosic derivatives and mixtures thereof and is present in anamount in the range of about 0.05% to about 0.5% (w/v). Without wishingto limit the invention to any particular theory of operation, it isbelieved that the presence of a viscosity inducing component at leastassists in providing the lens wearer/user comfort and acceptabilitybenefits of the present invention, which promote regular and consistentcontact lens care and ultimately lead to or facilitate better ocularhealth. The present combinations of components, for example, includingsuch viscosity inducing components, are effective in providing thedegree of lens wearer/user comfort and acceptability benefits describedherein.

[0012] Although any suitable, preferably ophthalmically acceptable,tonicity component may be employed, a very useful tonicity component isa combination of sodium chloride and potassium chloride.

[0013] The present compositions preferably include an effective amountof a chelating component. Any suitable, preferably ophthalmicallyacceptable, chelating component may be included in the presentcompositions, although ethylenediaminetetraacetic acid (EDTA), saltsthereof and mixtures thereof are particularly effective. Morepreferably, the present compositions include chelating components ineffective amounts less than about 0.05% (w/v) and still more preferably0.02% (w/v) or less. Such reduced amounts of chelating component in thepresent compositions remain effective in providing the desired chelatingand/or sequestering functions while, at the same time, are bettertolerated in the eye, thereby reducing the risk of user discomfortand/or ocular irritation.

[0014] Various combinations of two or more of the above-noted componentsmay be used in providing at least one of the benefits described herein.Therefore, each and every such combination is included within the scopeof the present invention.

[0015] These and other aspects of the present invention are apparent inthe following detailed description, examples and claims.

DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention is directed to multi-purpose solutionsuseful for treating, for example, disinfecting, cleaning, soaking,rinsing, wetting, conditioning and the like, contact lenses. Any contactlenses, for example, conventional hard contact lenses, rigid gaspermeable contact lenses and soft, hydrophilic or hydrogel, contactlenses, can be treated in accordance with the present invention.

[0017] In one embodiment, the present compositions comprise a liquidaqueous medium; an antimicrobial component in the liquid aqueous mediumin an amount effective to disinfect a contact lens contacted with thecomposition; a surfactant, preferably a non-ionic surfactant, componentin an amount effective in cleaning a contact lens contacted with thecomposition; a phosphate buffer component in an amount effective inmaintaining the pH of the composition within a physiologicallyacceptable range; an effective amount of a viscosity inducing component;and an effective amount of a tonicity component. The presentcompositions preferably include an effective amount of a chelating orsequestering component, more preferably in a range of less than 0.05%(w/v). Each of the components, in the concentration employed, includedin the solutions and the formulated solutions of the present inventionpreferably are ophthalmically acceptable. In addition, each of thecomponents, in the concentration employed, included in the presentsolutions preferably is soluble in the liquid aqueous medium.

[0018] A solution or component thereof is “ophthalmically acceptable”when it is compatible with ocular tissue, that is, it does not causesignificant or undue detrimental effects when brought into contact withocular tissue. Preferably, each component of the present compositions isalso compatible with the other components of the present compositions.The present compositions are more preferably substantiallyophthalmically optimized. An ophthalmically optimized composition is onewhich, within the constraints of component chemistry, minimizes ocularresponse, or conversely delivers ophthalmic benefit to the lens wearingeye.

[0019] The presently useful antimicrobial components include chemicalswhich derive their antimicrobial activity through a chemical orphysiochemical interaction with microbes or microorganisms, such asthose contaminating a contact lens. Suitable antimicrobial componentsare those generally employed in ophthalmic applications and include, butare not limited to, quaternary ammonium salts used in ophthalmicapplications such as poly[dimethylimino-2-butene-1,4-diyl] chloride,alpha-[4-tris(2-hydroxyethyl) ammonium]-dichloride (chemical registrynumber 75345-27-6, available under the trademark Polyquaternium 1® fromOnyx Corporation), benzalkonium halides, and biguanides, such as saltsof alexidine, alexidine-free base, salts of chlorhexidine, hexamethylenebiguanides and their polymers, and salts thereof, antimicrobialpolypeptides, chlorine dioxide precursors, and the like and mixturesthereof. Generally, the hexamethylene biguanide polymers (PHMB), alsoreferred to as polyaminopropyl biguanide (PAPB), have molecular weightsof up to about 100,000. Such compounds are known and are disclosed inOgunbiyi et al U.S. Pat. No. 4,758,595, the disclosure of which ishereby incorporated in its entirety by reference herein.

[0020] The antimicrobial components useful in the present inventionpreferably are present in the liquid aqueous medium in concentrations inthe range of about 0.00001% to about 2% (w/v).

[0021] More preferably, the antimicrobial component is present in theliquid aqueous medium at an ophthalmically acceptable or safeconcentration such that the user can remove the disinfected lens fromthe liquid aqueous medium and thereafter directly place the lens in theeye of safe and comfortable wear.

[0022] The antimicrobial components suitable for inclusion in thepresent invention include chlorine dioxide precursors. Specific examplesof chlorine dioxide precursors include stabilized chlorine dioxide(SCD), metal chlorites, such as alkali metal and alkaline earth metalchlorites, and the like and mixtures thereof. Technical grade sodiumchlorite is a very useful chlorine dioxide precursor. Chlorinedioxide-containing complexes such as complexes of chlorine dioxide withcarbonate, chlorine dioxide with bicarbonate and mixtures thereof arealso included as chlorine dioxide precursors. The exact chemicalcomposition of many chlorine dioxide precursors, for example, SCD andthe chlorine dioxide complexes, is not completely understood. Themanufacture or production of certain chlorine dioxide precursors isdescribed in McNicholas U.S. Pat. No. 3,278,447, which is incorporatedin its entirety herein by reference. Specific examples of useful SCDproducts include that sold under the trademark Dura Klor by Rio LindaChemical Company, Inc., and that sold under the trademark AnthiumDioxide by International Dioxide, Inc.

[0023] If a chlorine dioxide precursor in included in the presentcompositions, it preferably is present in an effective contact lensdisinfecting amount. Such effective disinfecting concentrationspreferably are in the range of about 0.002 to about 0.06% (w/v) of thepresent compositions. Such chlorine dioxide precursors may be used incombination with other antimicrobial components, such as biguanides,biguanide polymers, salts thereof and mixtures thereof.

[0024] In the event that chlorine dioxide precursors are employed asantimicrobial components, the compositions preferably have an osmolalityof at least about 200 mOsmol/kg and are buffered to maintain the pHwithin an acceptable physiological range, for example, a range of about6 to about 10.

[0025] In one embodiment, the antimicrobial component is non-oxidative.It has been found that reduced amounts of non-oxidative antimicrobialcomponents, for example, in a range of about 0.1 ppm to about 3 ppm orless than 5 ppm (w/v), in the present compositions are effective indisinfecting contact lenses and reduce the risk of such antimicrobialcomponents causing ocular discomfort and/or irritation. Such reducedconcentration of antimicrobial component is very useful when theantimicrobial component employed is selected from biguanides, biguanidepolymers, salts thereof and mixtures thereof.

[0026] When a contact lens is desired to be disinfected by the presentcompositions, an amount of the antimicrobial component effective todisinfect the lens is used. Preferably, such an effective amount of theantimicrobial component reduces the microbial burden or load on thecontact lens by one log order in three hours. More preferably, aneffective amount of the disinfectant reduces the microbial load by onelog order in one hour.

[0027] The phosphate buffer component is present in an amount effectiveto maintain the pH of the composition or solution in the desired range,for example, in a physiologically acceptable range of about 4 or about 5or about 6 to about 8 or about 9 or about 10. In particular, thesolution preferably has a pH in the range of about 6 to about 8. Thephosphate buffer component preferably includes one or more phosphatebuffers, for example, combinations of monobasic phosphates, dibasicphosphates and the like. Particularly useful phosphate buffers are thoseselected from phosphate salts of alkali and/or alkaline earth metals.Examples of suitable phosphate buffers include one or more of sodiumdibasic phosphate (Na₂HPO₄), sodium monobasic phosphate (NaH₂PO₄) andpotassium monobasic phosphate (KH₂PO₄). The present buffer componentsfrequently are used in amounts in a range of about 0.01% or about 0.02%to about 0.5% (w/v), calculated as phosphate ion.

[0028] The present compositions preferably further comprise effectiveamounts of one or more additional components, such as a detergent orsurfactant component; a viscosity inducing or thickening component; achelating or sequestering component; a tonicity component; and the likeand mixtures thereof. The additional component or components may beselected from materials which are known to be useful in contact lenscare compositions and are included in amounts effective to provide thedesired effect or benefit. When an additional component is included, itis preferably compatible under typical use and storage conditions withthe other components of the composition. For instance, the aforesaidadditional component or components preferably are substantially stablein the presence of the antimicrobial and buffer components describedherein.

[0029] A surfactant component preferably is present in an amounteffective in cleaning, that is to at least facilitate removing, andpreferably effective to remove, debris or deposit material from, acontact lens contacted with the surfactant-containing solution.Exemplary surfactant components include, but are not limited to,nonionic surfactants, for example, polysorbates (such as polysorbate20-Trademark Tween 20), 4-(1,1,3,3-tetramethylbutyl)phenol/poly(oxyethylene) polymers (such as the polymer sold under thetrademark Tyloxapol), poly(oxyethylene)-poly(oxypropylene) blockcopolymers, glycolic esters of fatty acids and the like, and mixturesthereof.

[0030] The surfactant component preferably is nonionic, and morepreferably is selected from poly(oxyethylene)-poly(oxypropylene) blockcopolymers and mixtures thereof. Such surfactant components can beobtained commercially from the BASF Corporation under the trademarkPluronic®. Such block copolymers can be generally described aspolyoxyethylene/polyoxypropylene condensation polymers terminated inprimary hydroxyl groups. They may be synthesized by first creating ahydrophobe of desired molecular weight by the controlled addition ofpropylene oxide to the two hydroxyl groups of propylene glycol. In thesecond step of the synthesis, ethylene oxide is added to sandwich thishydrophobe between hydrophile groups.

[0031] In accordance with a more preferred embodiment of the invention,such block copolymers having molecular weights in the range of about2500 to 13,000 daltons are suitable, with a molecular weight range ofabout 6000 to about 12,000 daltons being still more preferred. Specificexamples of surfactants which are satisfactory include: poloxamer 108,poloxamer 188, poloxamer 237, poloxamer 238, poloxamer 288 and poloxamer407. Particularly good results are obtained poloxamer 237.

[0032] The amount of surfactant component, if any, present varies over awide range depending on a number of factors, for example, the specificsurfactant or surfactants being used, the other components in thecomposition and the like. Often the amount of surfactant is in the rangeof about 0.005% or about 0.01% to about 0.1% or about 0.5% or about 0.8%(w/v).

[0033] The viscosity inducing components employed in the presentsolutions preferably are effective at low or reduced concentrations, arecompatible with the other components of the present solutions and arenonionic. Such viscosity inducing components are effective to enhanceand/or prolong the cleaning and wetting activity of the surfactantcomponent and/or condition the lens surface rendering it morehydrophilic (less lipophilic) and/or to act as a demulcent on the eye.Increasing the solution viscosity provides a film on the lens which mayfacilitate comfortable wearing of the treated contact lens. Theviscosity inducing component may also act to cushion the impact on theeye surface during insertion and serves also to alleviate eyeirritation.

[0034] Suitable viscosity inducing components include, but are notlimited to, water soluble natural gums, cellulose-derived polymers andthe like. Useful natural gums include guar gum, gum tragacanth and thelike. Useful cellulose-derived viscosity inducing components includecellulose-derived polymers, such as hydroxypropyl cellulose,hydroxypropylmethyl cellulose, carboxymethyl cellulose, methylcellulose, hydroxyethyl cellulose and the like. More preferably, theviscosity inducing agent is selected from cellulose derivatives(polymers) and mixtures thereof.

[0035] A very useful viscosity inducing component is hydroxypropylmethylcellulose (HPMC).

[0036] The viscosity inducing component is used in an amount effectiveto increase the viscosity of the solution, preferably to a viscosity inthe range of about 1.5 to about 30, or even as high as about 750, cps at25° C., preferably as determined by USP test method No. 911 (USP 23,1995). To achieve this range of viscosity increase, an amount ofviscosity inducing component of about 0.01% to about 5% (w/v) preferablyis employed, with amounts of about 0.05% to about 0.5% being morepreferred.

[0037] A chelating or sequestering component preferably is included inan amount effective to enhance the effectiveness of the antimicrobialcomponent and/or to complex with metal ions to provide more effectivecleaning of the contact lens.

[0038] A wide range of organic acids, amines or compounds which includean acid group and an amine function are capable of acting as chelatingcomponents in the present compositions. For example, nitrilotriaceticacid, diethylenetriaminepentacetic acid,hydroxyethylethylene-diaminetriacetic acid, 1,2-diaminocyclohexanetetraacetic acid, hydroxyethylaminodiacetic acid,ethylenediamine-tetraacetic acid and its salts, polyphosphates, citricacid and its salts, tartaric acid and its salts, and the like andmixtures thereof, are useful as chelating components.Ethylenediaminetetraacetic acid (EDTA) and its alkali metal salts, arepreferred, with disodium salt of EDTA, also known as disodium edetate,being particularly preferred.

[0039] The chelating component preferably is present in an effectiveamount, for example, in a range of about 0.01% and about 1% (w/v) of thesolution.

[0040] In a very useful embodiment, particularly when the chelatingcomponent is EDTA, salts thereof and mixtures thereof, a reduced amountis employed, for example, in the range of less than about 0.05% (w/v) oreven about 0.02% (w/v) or less. Such reduced amounts of chelatingcomponent have been found to be effective in the present compositionswhile, at the same time, providing for reduced discomfort and/or ocularirritation.

[0041] The liquid aqueous medium used is selected to have no substantialdeleterious effect on the lens being treated, or on the wearer of thetreated lens. The liquid medium is constituted to permit, and evenfacilitate, the lens treatment or treatments by the presentcompositions. The liquid aqueous medium advantageously has an osmolalityin the range of at least about 200 mOsmol/kg for example, about 300 orabout 350 to about 400 mOsmol/kg. The liquid aqueous medium morepreferably is substantially isotonic or hypertonic (for example,slightly hypertonic) and/or is ophthalmically acceptable.

[0042] The liquid aqueous medium preferably includes an effective amountof a tonicity component to provide the liquid medium with the desiredtonicity. Such tonicity components may be present in the liquid aqueousmedium and/or may be introduced into the liquid aqueous medium. Amongthe suitable tonicity adjusting components that may be employed arethose conventionally used in contact lens care products, such as variousinorganic salts. Sodium chloride and/or potassium chloride and the likeare very useful tonicity components. The amount of tonicity componentincluded is effective to provide the desired degree of tonicity to thesolution. Such amount may, for example, be in the range of about 0.4% toabout 1.5% (w/v). If a combination of sodium chloride and potassiumchloride is employed, it is preferred that the weight ratio of sodiumchloride to potassium chloride be in the range of about 3 to about 6 orabout 8.

[0043] Methods for treating a contact lens using the herein describedcompositions are included within the scope of the invention. Suchmethods comprise contacting a contact lens with such a composition atconditions effective to provide the desired treatment to the contactlens.

[0044] The contacting temperature is preferred to be in the range ofabout 0° C. to about 100° C., and more preferably in the range of about10° C. to about 60° C. and still more preferably in the range of about15° C. to about 30° C. Contacting at or about ambient temperature isvery convenient and useful. The contacting preferably occurs at or aboutatmospheric pressure. The contacting preferably occurs for a time in therange of about 5 minutes or about 1 hour to about 12 hours or more.

[0045] The contact lens can be contacted with the liquid aqueous mediumby immersing the lens in the medium. During at least a portion of thecontacting, the liquid medium containing the contact lens can beagitated, for example, by shaking the container containing the liquidaqueous medium and contact lens, to at least facilitate removal ofdeposit material from the lens. After such contacting step, the contactlens may be manually rubbed to remove further deposit material from thelens. The cleaning method can also include rinsing the lenssubstantially free of the liquid aqueous medium prior to returning thelens to a wearer's eye.

[0046] The following non-limiting examples illustrate certain aspects ofthe present invention.

EXAMPLE 1

[0047] A solution is prepared by blending together the followingcomponents: PHMB 1 ppm (w/v) (polyhexamethylene biguanide) Disodium EDTA0.02% (w/v) Poloxamer 237 0.05% (w/v) (poly(oxyethylene)-poly(oxypropylene) block copolymer) Sodium Phosphate 0.12% (w/v) Dibasic(heptahydrate) Sodium Phosphate 0.01% (w/v) Monobasic (monohydrate) HPMC(Hydroxypropylmethyl 0.15% (w/v) Cellulose) Sodium Chloride 0.79% (w/v)Potassium Chloride 0.14% (w/v) Water (USP) Q.S. 100%

[0048] Approximately three (3) ml of this solution is introduced into alens vial containing a lipid, oily deposit laden, hydrophilic or softcontact lens. The contact lens is maintained in this solution at roomtemperature for at least about four (4) hours. This treatment iseffective to disinfect the contact lens. In addition, it is found that asubstantial portion of the deposits previously present on the lens hasbeen removed. This demonstrates that this solution has substantialpassive contact lens cleaning ability. Passive cleaning refers to thecleaning which occurs during soaking of a contact lens, withoutmechanical or enzymatic enhancement.

[0049] After this time, the lens is removed from the solution and isplaced in the lens wearer's eye for safe and comfortable wear.Alternately, after the lens is removed from the solution, it is rinsedwith another quantity of this solution and the rinsed lens is thenplaced in the lens wearer's eye for safe and comfortable wear.

EXAMPLE 2

[0050] Example 1 is repeated except that the lens is rubbed and rinsedwith a different quantity of the solution prior to being placed in thelens vial. After at least about four (4) hours, the lens is removed fromthe solution. The lens is then placed in the lens wearer's eye for safeand comfortable wear.

EXAMPLE 3

[0051] The solution of Example 1 is used as a long-term soaking mediumfor a hydrophilic contact lens. Thus, approximately three (3) ml of thissolution is placed in a vial and a contact lens is maintained in thesolution at room temperature for about sixty (60) hours. After thissoaking period, the lens is removed from the solution and placed in thelens wearer's eye for safe and comfortable wear. Alternately, after thelens is removed from the solution, it is rinsed with another quantity ofthis solution and the rinsed lens is then placed in the lens wearer'seye for safe and comfortable wear.

EXAMPLE 4

[0052] A hydrophilic contact lens is ready for wear. In order tofacilitate such wearing, one or two drops of the solution of Example 1is placed on the lens immediately prior to placing the lens in the lenswearer's eye. The wearing of this lens is comfortable and safe.

EXAMPLE 5

[0053] A lens wearer wearing a contact lens applies one or two drops ofthe solution of Example 1 in the eye wearing the lens. This effects are-wetting of the lens and provides for comfortable and safe lens wear.

EXAMPLE 6

[0054] A series of tests are conducted to evaluate the comfort, safetyand acceptability of the solution prepared in accordance with Example 1compared to two other solutions.

[0055] The first of these other solutions, referred to hereinafter asComposition A, is sold under the trademark ReNu® by Bausch & Lomb andincludes 0.5 ppm PHMB, a poly(oxyethylene)-poly(oxypropylene)substituted ethylenediamine surfactant, a borate buffer system, 0.1%disodium EDTA, and sodium chloride as a tonicity agent.

[0056] The second of these other solutions, referred to hereinafter asComposition B, is similar to the composition of Example 1 except thatComposition B included 0.6% (w/v) tromethamine, and neither of thephosphates.

[0057] Each of these compositions is tested to evaluate its comfort,safety and acceptability for the care of hydrogel (hydrophilic) contactlenses worn on a daily basis among subjects previously adapted to atleast one commercially available multi-purpose solution.

[0058] The study is a randomized, double-masked, three-way cross overstudy. The study is broken down into a series of three (3) one (1) monthtreatment periods. Each of the compositions is used on a daily basis forcleaning, rinsing after cleaning, disinfection, and rinsing prior tolens application, as needed. Because each treatment period is only one(1) month in duration, no enzymatic cleaner is used in this study.

[0059] The subjects are evaluated at day zero (baseline), day seven (7)and day thirty (30) for each of the three (3) treatment periods. Theprimary comfort and acceptability variables are lens wearing comfort andend of study product preference. The primary safety variable is slitlamp examination findings.

[0060] 123 subjects are enrolled. 116 (94.3%) complete PreferenceQuestionnaires for Treatment Period 2. 118 (95.9%) complete PreferenceQuestionnaires for Treatment Period 3.

[0061] The results of this study are summarized as follows. The slitlamp examinations indicate that each of the compositions tested isacceptably safe. The comfort and acceptability results included in thissummary are based on subjective answers to selected questions (at theend of Treatment Periods 2 and 3).

[0062] Further tabulations are made based on subjective answers to theselected questions noted above, as well as to other questions includedin the Preference Questionnaires. These tabulations are made usinganswers from the Preference Questionnaires for Treatment Period 3.

[0063] Results of these further tabulations are as follows: RespondentsPreferring Respondents Example 1 Preferring Composition Composition A NoP Preference Question % % Preference Value Overall preference 65 28 70.02 In-the-hand preference 56 27 17 0.02 In-the-eye preference 63 27 110.02 Comfort in-the-eye 60 25 15 0.02 Amount of time for 47 21 32 0.02lenses to settle in the eye Keeping lenses moist 55 28 17 0.02 in eyesKeeping lenses 57 28 15 0.02 lubricated in eyes Soothing in eyes 57 2716 0.02

[0064] Respondents Preferring Respondents Composition B PreferringComposition Composition A No P Preference Question % % Preference ValueOverall preference 55 40 5 0.18 In-the-hand 51 31 18 0.08 preferenceIn-the-eye 60 34 6 0.02 preference Comfort in-the-eye 36 34 10 0.06Amount of time for 44 31 25 0.26 lenses to settle in the eye Keepinglenses 47 34 19 0.26 moist in eyes Keeping lenses 47 32 21 0.18lubricated in eyes Soothing in eyes 57 32 10 0.02

[0065] These results indicate a clear preference of the composition ofExample 1 over Composition A; and an overall preference of thecomposition of Example 1 over Composition B.

[0066] These results are indeed surprising since Composition A is acommercially available multi-purpose solution. Possible reasons for thepreference of the Example 1 composition relative to Composition Ainclude one or more of the presence of HPMC, the presence of apoly(oxyethylene)-poly(oxypropylene) block copolymer surfactant, thepresence of the phosphate buffer, and/or the presence of a reducedamount of EDTA.

[0067] The present compositions provide a very beneficial andadvantageous combination of performance efficacy and lens wearer/usercomfort and acceptability. In the context of contact lens caresolutions, lens wearer/user comfort and acceptability are veryimportant, for example, to promote regular and effective treating ofcontact lenses. Such treating of contact lenses ultimately promotesocular health and reduces the frequency of problems caused by wearingcontact lenses. Thus, lens wearer/user comfort and acceptability are ofsubstantial importance and benefit in a contact lens care product, inparticular in the present compositions which exhibit substantial, evenenhanced, lens wearer/user comfort and acceptability.

[0068] While this invention has been described with respect to variousspecific examples and embodiments, it is to be understood that theinvention is not limited thereto and that it can be variously practicedwithin the scope of the following claims.

What is claimed is:
 1. A multi-purpose solution for contact lens carecomprising: an aqueous liquid medium; an antimicrobial component in anamount effective to disinfect a contact lens contacted with saidsolution, said non-oxidative antimicrobial component being selected fromthe group consisting of biguanides, biguanide polymers, salts thereofand mixtures thereof, and being present in an amount in a range of about0.1 ppm to about 3 ppm; a poly(oxyethylene)-poly(oxypropylene) blockcopolymer surfactant in an amount effective in cleaning a contact lenscontacted with said solution; a phosphate buffer component in an amounteffective in maintaining the pH of said solution within aphysiologically acceptable range; a viscosity inducing componentselected from the group consisting of cellulosic derivatives andmixtures thereof in an effective amount in a range of about 0.05% toabout 0.5% (w/v); a chelating component in an effective amount of lessthan 0.05%(w/v); and a tonicity component in an amount effective inproviding the desired tonicity to said solution.
 2. The multi-purposesolution of claim 1 wherein said antimicrobial component is selectedfrom the group consisting of polyhexamethylene biguanide, salts thereofand mixtures thereof.
 3. The multi-purpose solution of claim 1 whereinsaid surfactant is present in an amount in the range of about 0.01% toabout 0.8%(w/v).
 4. The multi-purpose solution of claim 1 wherein saidphosphate buffer component includes a combination of sodium hydrogenphosphate and sodium dihydrogen phosphate.
 5. The multi-purpose solutionof claim 1 wherein said phosphate buffer component is present in anamount in a range of about 0.01% to about 0.5% (w/v).
 6. Themulti-purpose solution of claim 1 wherein said viscosity inducingcomponent is hydroxypropylmethyl cellulose.
 7. The multi-purposesolution of claim 1 wherein said tonicity component includes acombination of sodium chloride and potassium chloride and is present ina range of about 0.4% to about 1.5% (w/v).
 8. The multi-purpose solutionof claim 1 wherein said chelating component is EDTA.
 9. A multi-purposesolution for contact lens care comprising: an aqueous liquid medium; anantimicrobial component selected from the group consisting ofbiguanides, biguanide polymers, salts thereof and mixtures thereof, andbeing present in an amount in a range of about 0.1 ppm to less than 5ppm; a surfactant component in an amount effective in cleaning a contactlens contacted with said solution; a phosphate buffer component in anamount effective in maintaining the pH of said solution within aphysiologically acceptable range; a viscosity inducing component in anamount effective in increasing the viscosity of said solution; and atonicity component in an amount effective in providing the desiredtonicity to said solution.
 10. The multi-purpose solution of claim 9wherein said antimicrobial component is selected from the groupconsisting of polyhexamethylene biguanide, salts thereof and mixturesthereof.
 11. The multi-purpose solution of claim 9 wherein saidviscosity inducing component is hydroxypropylmethyl cellulose.
 12. Themulti-purpose solution of claim 9 wherein said surfactant is selectedfrom the group consisting of poly(oxyethylene)-poly(oxypropylene) blockcopolymers and mixtures thereof, and is present in an amount in a rangeof about 0.01% to about 0.8% (w/v).
 13. The multi-purpose solution ofclaim 9 wherein said tonicity component includes a combination of sodiumchloride and potassium chloride and is present in a range of about 0.4%to about 1.5% (w/v).
 14. The multi-purpose solution of claim 9 whichfurther comprises an effective amount of EDTA in a range of less than0.05% (w/v).
 15. A multi-purpose solution for contact lens carecomprising: an aqueous liquid medium; an antimicrobial component in anamount effective to disinfect a contact lens contacted with saidsolution; a surfactant component in an amount effective in cleaning acontact lens contacted with said solution; a phosphate buffer componentin an amount effective in maintaining the pH of said solution within aphysiologically acceptable range; a viscosity inducing componentselected from the group consisting of cellulosic derivatives andmixtures thereof and being present in an effective amount in a range ofabout 0.05% to about 0.50% (w/v); a chelating component in an effectiveamount of less than 0.05% (w/v); and a tonicity component in an amounteffective in providing the desired tonicity to said solution.
 16. Themulti-purpose solution of claim 15 wherein said viscosity inducingcomponent is hydroxypropylmethyl cellulose.
 17. The multi-purposesolution of claim 15 wherein said chelating agent is EDTA.
 18. Themulti-purpose solution of claim 15 wherein said antimicrobial componentis selected from the group consisting of biguanides, biguanide polymers,salts thereof and mixtures thereof, and is present in an amount in arange of about 0.1 ppm to less than 5 ppm.
 19. The multi-purposesolution of claim 18 wherein said antimicrobial component is selectedfrom the group consisting of polyhexamethylene biguanide, salts thereofand mixtures thereof.
 20. The multi-purpose solution of claim 15 whereinsaid surfactant is present in an amount in a range of about 0.01% toabout 0.8% (w/v).